In the show this time, Dr Álvaro Sánchez Monge tells us about High Mass Star Formation, Dr Evan Keane discusses magnetic fields and pulsars in this month's JodBite, and your astronomical questions are answered by Prof. Tim O'Brien in Ask an Astronomer.
JodBite with Dr Evan Keane
Dr. Evan Keane, formerly of the University of Manchester but now at Swinburne University of Technology, talks to us about a very rare find near the centre of our galaxy: a magnetar. He explains what magnetars are, why finding one near the centre is exceedingly rare, and how it can tell us a lot about the magnetic field in that area. The Nature paper that resulted from their discovery can be found here.
Interview with Dr Álvaro Sánchez MongeDr Álvaro Sánchez Monge researches high-mass star formation at the Osservatorio Astrofisico di Arcetri in Florence, just around the corner from Galileo's house. He talks about the difficulty of separating the different phases in the formation of high-mass stars, and how infrared observations help us to see into the compact clouds where they form. He tells us about how to identify the jets of material ejected from protostellar cores, the use of molecules to trace the different areas and stages of formation and how the ALMA telescope will show more detail in these regions than ever before, peering into the circumstellar discs which are condensing into planets even as their host star is being born. He explains that such observations are already challenging theoretical models of star formation, as they are showing more intense emission at certain frequencies than had been predicted.
Ask an Astronomer
Prof. Tim O'Brien answers your astronomical questions:
- Derek Kilkenny-Blake says: "We all know that the Earth takes approximately 365 days to make a full orbit of the Sun. The number of degrees in a circle is 360. Some say one possible explanation is that it is an approximation of the Earth's orbital rhythm. If the Earth orbited the Sun in a perfect circle, would it take 360 days to complete the task? If we drew a circle and then overlaid the ellipse of Earth's actual orbit on top of the circle, would the extra bulge on each side of the circle be roughly equivalent to 2.5 days on each side of the bulge? Or is it simply nowhere near that easy?"
- Pat O'Grady says: "My understanding is that long-period comets come from the Oort cloud, and that some event pushes them out of their orbit and in towards the Sun and the inner Solar System. When they have come by and gone back out again towards the Oort cloud, what stops them going past and off into deep space? Doesn't the Sun's influence end at the heliosphere?"
In his answer, Tim inadvertently presaged the latest account of Voyager's 'departure from the Solar System'. The edge of the Solar System, as Tim explains, is difficult to define, and a similar story has been reported several times before.
- Great Old Mac says: "Many detailed images of planetary nebulae have streamers of material, mostly in silhouette, which are usually described as 'knots'. With the recent Hubble images of M57 in Lyra, NASA provided a scale which indicated that they form at about one light-year from the central stars, where their orbital velocity would be close to zero. Do the spectra indicate that the knots and streamers are really super-comets?"
Odds and Ends
The Voyager 1 probe was announced to have entered interstellar space . The craft is currently some 19 billion km or 121 AU from the Earth, and was deemed by project scientists to have left the Sun's area of influence. Readings from the probe's onboard Plasma Wave Science instrument showed a hundred-fold increase in the proton density around the craft, thus showing that the Sun's magnetic field and solar wind had lost their influence on the surrounding space.
September 6th saw the launch of NASAs Lunar Atmosphere and Dust Environment Explorer (LADEE), a robotic mission designed to collect data on the moon's atmosphere and surface dust. Also timed to coincide with LADEE's take-off was the launch of the NASA instagram profile, making a internet star out of photobombing frog captured by remote cameras at the LADEE launch site.
August 31st was the deadline for applications for the Astronaut Selection Program for Mars One: a project run by a Dutch foundation that aims to establish the first human settlement on Mars. The estimated cost of the project is $6 billion, which the foundation hope to raise by turning the project into a reality TV style event, selling TV rights and corporate sponsorship.
|JodBite:||Dr Evan Keane and Indy Leclercq|
|Interview:||Dr Álvaro Sánchez Monge and Mark Purver|
|Ask An Astronomer:||Prof. Tim O'Brien and Mark Purver|
|Presenters:||Cat McGuire, Indy Leclercq and Joe Zuntz|
|Editors:||Adam Avison, Indy Leclercq, Cat McGuire and Mark Purver|
|Segment Voice:||Mike Peel|
|Website:||Cat McGuire and Stuart Lowe|
|Cover art:||Airborne frog at NASA's LADEE launch. The image was captured by one of the remote cameras at the Wallops Flight Facility in Virginia. CREDIT: Credit: NASA Wallops Flight Facility/Chris Perry|